[PATCH v3 1/3] scsi: ufs: Extract devfreq registration

From: Bjorn Andersson
Date: Fri May 18 2018 - 01:31:07 EST


Failing to register with devfreq leaves hba->devfreq assigned, which
causes the error path to dereference the ERR_PTR(). Rather than bolting
on more conditionals, move the call of devm_devfreq_add_device() into
it's own function and only update hba->devfreq once it's successfully
registered.

The subsequent patch builds upon this to make UFS actually work again,
as it's been broken since f1d981eaecf8 ("PM / devfreq: Use the available
min/max frequency")

Also switch to use DEVFREQ_GOV_SIMPLE_ONDEMAND constant.

Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---

Changes since v2:
- Use DEVFREQ_GOV_SIMPLE_ONDEMAND, per Chanwoo's recommendation
- Picked up Chanwoo's R-b

Changes since v1:
- None

drivers/scsi/ufs/ufshcd.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 00e79057f870..f04902a066cb 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1287,6 +1287,26 @@ static struct devfreq_dev_profile ufs_devfreq_profile = {
.get_dev_status = ufshcd_devfreq_get_dev_status,
};

+static int ufshcd_devfreq_init(struct ufs_hba *hba)
+{
+ struct devfreq *devfreq;
+ int ret;
+
+ devfreq = devm_devfreq_add_device(hba->dev,
+ &ufs_devfreq_profile,
+ DEVFREQ_GOV_SIMPLE_ONDEMAND,
+ NULL);
+ if (IS_ERR(devfreq)) {
+ ret = PTR_ERR(devfreq);
+ dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);
+ return ret;
+ }
+
+ hba->devfreq = devfreq;
+
+ return 0;
+}
+
static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
{
unsigned long flags;
@@ -6439,16 +6459,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
sizeof(struct ufs_pa_layer_attr));
hba->clk_scaling.saved_pwr_info.is_valid = true;
if (!hba->devfreq) {
- hba->devfreq = devm_devfreq_add_device(hba->dev,
- &ufs_devfreq_profile,
- "simple_ondemand",
- NULL);
- if (IS_ERR(hba->devfreq)) {
- ret = PTR_ERR(hba->devfreq);
- dev_err(hba->dev, "Unable to register with devfreq %d\n",
- ret);
+ ret = ufshcd_devfreq_init(hba);
+ if (ret)
goto out;
- }
}
hba->clk_scaling.is_allowed = true;
}
--
2.17.0